Vibration isolation devices in vibration source attachment structures prevent vibrations produced by an engine or other vibration source from being transmitted to the subframe by absorbing these vibrations. Such vibration source attachment devices are known, as proposed, for example, in Patent Literature 1.
The vibration source attachment structure disclosed in Patent Document 1 has a vehicle body frame extending in a longitudinal or front-rear direction of the vehicle body, a subframe disposed below the vehicle body frame, and an engine attached to the subframe via a vibration isolation device. A flange (engine mount bracket) of the vibration isolation device is disposed on an attachment base provided on the subframe, and the vibration isolation device is attached to the subframe by bolting the flange to the attachment base.
Because of such a structure, more time is required to install and dismantle the subframe on the vehicle body frame as part of the maintenance operation involved in servicing, inspecting, and replacing the vibration isolation device, and improvements are therefore required in terms of the ease of maintenance.
In addition, due to the presence of the attachment base and the flange, the subframe and the vibration isolation device are therefore proportionally heavier, and result in a disadvantage in terms of minimizing the subframe resonance caused by the vibrations of the vibration source. The vibrations transmitted from the subframe to the vehicle body frame are transmitted to the inside of the vehicle passenger compartment. It is preferable that the vibrations and sound transmitted to the inside of the vehicle passenger compartment be minimized as much as possible in order to increase the riding enjoyment and comfort of the passenger.